Annular combustion chamber air flow arrangement about the fuel nozzle end



March 20, 1951 R. A. sFoRzlNl 2,545,495

- ANNULAR coMEusToN CHAMBER AIR ELow ARRANGEMENT ABOUT THE FUEL NozzLE END Flled Aug 6, 1947 INVENTOR R0 elfi/ ATTORNEY Patented Mar. 20, `1951 ANNULAR,y COMBUSTION CHAMBER AIR FLOW ARRANGEMENT ABOUT FUEL NOZZLE END Robert A.. sforzini, Toledn, ohio, assign-r to, AWestinghouse Electric Corporation, East Pittsburgh, Pa., a corporation, of Pennsylvania Appliation August 6, 1947,s'eria1No. 766,715

(o1. com-ien` 6 Claims;

This invention relates to gas turbine power plants and has for an object the provision of improved combustion apparatus for a gas turbine engine.

After continued operation of a gas turbine engine of the well-known type comprising a combustion chamber interposed between an air compressor, and a gas turbine operable by heated fluid 'under pressure to drive the compressor, undesired accumulation of solid products of fuel combustion, or coking, on andr about the fuel nozzles may begin 'to impede the proper atomization .and distribution of fuel .necessary for promotion of uniform combustion. Heavy deposits of coke one-half inch or more in thickness lin the apical region of the combustion chamber are Vention to provide an improved combustion apparatus for a gas turbine power plant including a combustion chamber having fuel nozzles located in an apical portion thereof, and means for directing axial streams of air under pressure through the apical region and over the nozzles and adjacent surfaces, thereby creating local turbulence effectively minimizing deposition of coke.

l Still another object is the provision of an improved combustion chamber structure for a gas turbine including means for establishing a localizing cooling blanket of circulating air under pressurev in the fuel injection region for preventing accumulation of coke deposits.

Other objects and advantages of the invention will appear in the following more detailed description thereof, taken in connection with the accompanying drawing, in which:

Figure 1 is a schematic elevational View, partlyin section, of a gas turbine power plant embodying an improved combustion apparatusconstructed in accordance with the invention; vligure 2 is a fragmentary elevational View in 'enlarged sectional detail of the combustion apparatusforming part of the power plant shown in Figure 1; and

Figures 3 and 4 are fragmentary sectional views takensubstantially along the lines III- THE 2 lustrative gas turbine power plant of' the type with which my invention may be associated mayl comprise an outer casing structure I0 in which is supported an inner casing structure Il, forming an annular passageway I2 which extends longitudinally of the plant from a forward intake opening I 3 to a rearwardly-disposed discharge nozzle I4. The power plant is adapted to be mounted in or on the fuselage or wing of an air craft, with the intake opening I3 pointed in the direction of flight. Mounted within the casing I9 along the longitudinal axis thereof are a fairing member or core section Ity 'which may house auxiliary control apparatus (not shown), an axial-flow compressor Il, combustion apparatus I8 including a generally annular fuel combustor or basket structure I9, and a two-stage turbine 29, the rotor of which is operatively connected to the rotor of compressor I'I by means of a common shaft 2l. The shaft 2| may be journaled in suitable bearings 22 carried by the inner casing structure Il. Rearwardly of the turbine 20 is mounted a centrally-disposed tail'- f piece 23, which may be arranged for adjustment to vary the flow area of the discharge nozzle I4.

In operation, air entering the intake opening I3 is supplied to the compressor I'I which delivers the air under pressure to the combustion apparatus I3, in which fuel is burned at temperatures ranging between 900 and 3000"* F. From the combustion apparatus Ii! the heated 'motive fluid under pressure is expanded in the turbine 20 and is then discharged through the nozzle I4, usually in the form of a jet establishing a propulsion force.

The fuel combustor structure I9, in the form illustrated in the drawing', comprises outer cylindrical Wall sections 25, 26 and 2, which are 'successively larger in diameter, and inner cylindrical wall sections 23, 29 and 3D, which are successively smaller in diameter. The outer and inner wall sections 25 and 28 are concentrically aligned and arranged in partially telessoping relation with adjacent ends of the similarly arranged sections 2 and 29, the opposite ends of which are in turn partially telescoped within the forward ends of the rearward outer and inner sections 2i' and 3B. An inner spacer ring 33 having axial openings 34 (see Fig. 2) is interposed between the adjacent surfaces of the adjoining inner wall sections 2B and 29. An outer spacer ring 35 having axial openings 36 is likewise interposed. between the telescoped ends of the adjoiningsections .25 and 26. As shown in Fig. 1,. anapertured 4spacer ring '38 is in like.

manner interposed between the adjacent ends of the outer wall sections 26 and 2l', while a smaller spacer ring 3S is likewise interposed between the telescoping ends of the inner wall sections 29 and 3Q. It will thus be seen that the combustor structure i9 is, in eifect, provided with walls of stepped or substantially conical cross sections graduated inwardly to the forward or upstream end portion deiined between the wall sections 25 and 28, the entire structure enclosing a combustion chamber generally indicated by the reference character 11%.

As is best shown in Figure 2 of the drawing, the forward ends of the outer and inner wall sections 25 and 28 terminate in a common plane and are joined by an annular closure member or end section 23, which is provided with lateral flanges 44 and l5 adapted to be welded to the respective wall sections. Associated with the end section 43 is a fairing section "it enclosing an annular fuel manifold l, which is adapted to be supplied by fuel under pressure from a suitable source (not shown). The manifold Il? communicates with the combustion chamber El through the medium of a plurality of fuel injection nozzles 48, which are circumferentially spaced and are mounted in the end section 43 concentrically of the combustion chamber Gil. It will be understood that in operation, fuel is supplied under pressure through the manifold 4l' and is injected through the usual restricted ports in the several nozzles 48 into the combustion chamber fw, where the atomized fuel is ignited and burned, the combustion process being supported by air under pressure admitted from the passageway I2 to the combustion chamber by way of the apertures including the apertures 3A; and 36.

According to the invention, shielding means is provided within the upstream end portion of the combustion chamber 4Q in association with the nozzles e8* for directing auxiliary jets of air under pressure over the nozzles and adjacent surfaces for preventing accumulation of the undesired deposits of coke already mentioned. This shielding means may comprise an outer annular flange or baffle wall member i! supported by the outer wall section 25 closely adjacent the end section 43, and an annular flange or baille wall member 5l aligned with the flange` member 5S and supported on the inner wall section 28. The respective flange members 50 and 5I are adapted to form an annular space 52 communicating with combustion chamber 5S, the flange members being spaced apart to provide an annular fuel admission opening 553 through which atomized fuel can be eX- pelled from the nozzles i8 into the combustion chamber sii, as shown in Figure 2.

Formed in the end section i3 on opposite sides ofthe nozzles 'i3 are staggered rows of arcuate slots which are arranged to direct jets or streams of air under pressure from the passageway i2 through the space 52 and past the projecting flange members 56 and 5! into combustion chamber' 53. The flange members are adapted to deflect these streams of air under pressure toward the respective nozzles 48, which are thereby blanketed by currents of air circulating in the region wherein ccking might otherwise tend to develop. It will thus be seen that the flange members l constitute baiiles defining the space 52 which is continually swept clean by air under pressure admitted through the slots 55, the air under pressure being thence directed past the nozzles and through the annular opening 53 into thecombustion chamber` 40, wherethe combustion process is maintained. It will, furthermore, be apparent that in addition to the main function of the auxiliary streams of air under pressure admitted through the ports in minimizing formation of coke, the resultant turbulence in the region of the nozzles 48 will have a desirable cooling effect.

Auxiliary apertures and 5l are formed in the outer and inner wall sections 25 and 28, respectively, and in the adjacent anges of the respective flange members or ballles 50 and 5I, for directing laterally flowing streams of air under pressure across the downstream surfaces of the flange members, in order to prevent formation of coke deposits on these surfaces, as Well as to augment the sweeping action of the air under pressure issuing through the annular opening 53. The flange members 50 and 5| are at the same time adapted to constitute anchoring surfaces for facilitating maintenance of uniform and constant name characteristics within the combustion chamber lli).

From the foregoing it will now be apparent that an improved fuel combustion apparatus constructed in accordance with my invention may readily be installed in a gas turbine of existing design for minimizing the undesired development of coke deposits, without in any way reducing the.

eliiciency of the engine during service operation'.

While the invention has been shown in but one form, it will be obvious to those skilled in the'art that it is not so limited, but is susceptible l'of various changes and modifications without .de-v

parting from the spirit thereof.

What is claimed is:

l. Combustion apparatus for a gas turbine. engine having inner and outer casing sections defining an annular inlet passage for fluid under pressure ilcwing at high velocit an annular combustor structure supported therein comprising telescoped inner and outer walls graduated inwardly at the upstream end. joined by an annular flat end section to provide an annular combustion chamber, said end section being disposed normal to the path of fluid flowing through said passage, a plurality of circumferentially spaced fuel atomizing nozzles mounted in said end section for injecting fuel into the upstreaml end of said combustion chamber, radially spaced annular baffles mounted on said inner and outer walls adjacent and parallel to said end section; and a plurality of apertures formed in said end section for directing streams of fluid under pressure from said inlet flow passage against said bailles and said nozzles for minimizing accumulation thereon of fuel deposits.

2. Combustion apparatus for a gas turbine engine having inner and outer casing sections delining an annular inlet passage for fluid under pressure flowing at high velocity, an annular combustor structure supported thereinl comprislng telescoped inner and outer walls graduated inwardly at the upstream end, joined by an annular flat end section to provide an annular combustion chamber, said end section being disposed' normal to the path of fluid flowing through said' passage, a plurality of circumferentially spaced; fuel atomizing nozzles mounted on said end section for injecting fuel into the upstream end off said combustion chamber, said inner and outer walls having a plurality of spaced apertures formed therein downstream Yof said end section and adapted to supply fluid under pressure from" said inlet flow passage into said combustion chamber for supporting combustion of `fuel therein, radially spaced shield members carried by said inner and outer walls intermediate said apertures therein and said end section, said shield members being disposed in spaced relation adjacent said nozzles and parallel to said end section, said end section having a plurality of ports formed therein to direct fluid under pressure from said passage against said shield members in streams blanketing said nozzles for minimizing local accumulation of coke during the combustion of fuel in said combustion chamber.

3. Combustion apparatus for a gas turbine engine having inner and outer casing sections defining an annular inlet passage for fluid under pressure flowing at high velocity, an annular combustor structure supported therein comprising inner and outer walls closed at the upstream end by an annular end section to provide an annular combustion chamber, a plurality of circumferentially spaced fuel atomizing nozzles mounted in said end section for injecting fuel into the upstream end of said combustion chamber, said end section having concentric rows of auxiliary ports formed inwardly and outwardly of said nozzles and adapted to admit axially flowing streams of fluid under pressure from said passage to said combustion chamber adjacent said nozzles, and baie means mounted parallel to said end section in spaced relation with respect to said nozzles, said baille means being adapted to deflect fluid under pressure flowing from said ports for creating local turbulence in the region of said nozzles preventing deposit of fuel solids during combustion within said combustion chamber.

4. Combustion apparatus for a gas turbine engine having inner and outer casing sections dening an annular inlet passage for fluid under pressure flowing at high velocity, an annular combustor structure supported therein comprising telescoped inner and outer walls graduated inwardly at the upstream end, joined by an annular flat end section to provide an annular combustion chamber, said end section being disposed normal to the path of uid flowing through said passage,

a plurality of circumferentially spaced fuel atomizing nozzles mounted in said end section for injecting fuel into the upstream end of said combustion chamber, said flat wall of the end section having a plurality of auxiliary ports adapted to admit axially flowing streams of fluid under pressure from said passage to said combustion chamber adjacent said nozzles, and'baile means mounted near and parallel to said end lsection in shielding relation with said nozzles,

ning an annular inlet passage for fluid under pressure flowing at high velocity, an annular combustor structure supported therein comprising telescoped inner and outer walls graduated inwardly at the upstream end, joined by an annular flat end section to provide an annular combustion chamber,v said end section being disposed normal to the path of fluid flowing through said passage, a plurality of circumferentially spaced fuel atomizing nozzles mounted in said end section for injecting fuel into the upstream end of said combustion chamber, an annular baflie supported on said outer Wall within said combustion chamber, and an annular baifle supported on said inner Wallin spaced alignment with said firstnamed baliie, said baffles being mounted parallel to said end section in closely straddling relation with respect to said nozzles, said end section having a plurality of staggered arcuate slots through which fluid under pressure is directed from said inlet passage to be deflected by said bailes in streams blanketing said nozzles for minimizing local deposit of solid products of combustion.

6. Combustion apparatus for a gas turbine power plant having casing structure dening an annular passage for air under pressure flowing at high velocity, an annular sheet metal structure supported therein, comprising apertured inner and outer annular walls closed at the upstream end by an annular end section to form a combustion chamber having a main zone of combustion intermediate the ends thereof, said end section providing a flat annular Wall disposed substantially normal to the axis of said annular passage and having formed therein a plurality of nozzle openings interposed between concentric rows of auxiliary air ports, a pair of concentric annular flanges extending radially into said chamber from said inner and outer walls adjacent said endY section, said flanges forming a nozzle chamber upstream of said combustion zone and communicating through an annular opening with said combustion chamber, said inner and outer walls having closely spaced lateral ports adjacent said flanges for admitting air to scour the downstream surfaces thereof, anda plurality of fuel nozzles mounted in said nozzle openings of said end section in alignment with said annular opening between said fianges, said nozzles being subjected to a blanket of air owing into said nozzle chamber at high velocity through said auxiliary ports and impinging on said flanges for minimizing local deposition of coke.

ROBERT A. SFORZINI.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS 

